Method and apparatus for rebuilding valve guides

ABSTRACT

This disclosure relates to a method and system for rebuilding valve guides for internal combustion engines wherein the old worn guides are first reamed and then have slitted tubular members forced into the reamed guides. The tubular member inserts can then be reamed to size. The operation can also include knurling and broaching of the tubular members after insertion of the tubular member into the the reamed valve guide. The tubular member has an outer diameter greater than the inner diameter of the reamed guide so that a press fit between the tubular member and the guide results.

United States Patent 1191 Kammeraad et al.

1451 Aug. 13, 1974 METHOD AND APPARATUS FOR REBUILDING VALVE GUIDES [75]Inventors: James A. Kammeraad; Donald J.

Kammeraad, both of Holland, Mich.

[73] Assignee: K-Line Tool Company, Holland,

Mich.

221 Filed: Nov. 26, 1971 21 Appl. No; 202,207

Related US. Application Data [62] Division of Ser. No. 847,927, Aug. 6,1969,

abandoned.

52 us. on. 29/401, 29/156.4 WL, 29/235, 29/451, 29/525, 123/188 00 51lm. c1..... B23p 7/00, B23p 15/00, B23p 19/02 [58] Field of Search29/157.1, 213, 235, 401, 29/451, 525, 156.4 WL; 123/9057, 188 P,

188 VA, 188 cc, 188 SA; 308/5 v, 237 R [56] References Cited UNITEDSTATES PATENTS 1,640,118 8/1927 Ford 123/90.67 2,225,807 12/1940Towler..... 123/188 GC 2,275,310 3/1942 Nuttall .1 29/401 2,303,14511/1942 Taylor 308/5 V 2,361,434 10/1944 Surtees 29/156.4 WL 2,414,931l/l947 Colwell et a1 29/156.4 WL 2,562,359 7/1951 lredell 29/4512,618,182 11/1952 Teetor 29/156.4 WL

Surtees 29/156.4 WL

Primary Examiner-Charles W. Lanham Assistant Examiner-E. M. CombsAttorney, Agent, or Firm-Price, Heneveld, Huizenga & Cooper [5 7]ABSTRACT This disclosure relates to a method and system for rebuildingvalve guides for internal combustion engines wherein the old worn guidesare first reamed and then have slitted tubular members forced into thereamed guides. The tubular member inserts can then be reamed to size.The operation can also include knurling and broaching of the tubularmembers after insertion of the tubular member into the the reamed valveguide. The tubular member has an outer diameter greater than the innerdiameter of the reamed guide so that a press fit between the tubularmember and the guide results.

12 Claims, 8 Drawing Figures LLIIIIJIIIIIJIIII! PAIENFEB 31974 SHEET 2OF 2 METHOD AND APPARATUS FOR REBUILDING VALVE GUIDES This is a divisionof application Ser. No. 847,927 filed Aug. 6, 1969, now abandoned.

This invention relates to rebuilding valve guides. In one of itsaspects, it relates to rebuilding valve guides wherein the old guidesare first reamed and slitted tu bular members are then forced into thereamed guides.

In another of its aspects, the invention relates to a system forrebuilding valve guides in which a reaming means is provided to ream outthe old valve guide, a tubular member having a longitudinal slit isprovided, and means are provided for forcing the tubular member into areamed valve guide to provide a press fit between the reamed valve guideand the tubular member.

Valve guides for internal combustion engines become worn throughextended use. It is necessary for the valve guide to have closetolerances between the valve stem and the valve guides in order for theengine to operate efficiently.

Tools have been devised for effectively reducing the diameter of a holesuch as valve guides. In US. Pat. No. 3,097,426, for example, there isdisclosed a tool for reducing the effective diameter of a hole byforming flat crested threads within the hole. This tool cannot always beused for rebuilding valve guides, however, because in many instances thevalve guides are so badly worn that there is insufficient metal to formthe desired inner diameter of the guide.

Other systems have been developed for rebuilding valve guides. One suchsystem drills and reams out valve guides and then inserts a tubular castiron cylinder into the reamed out hole. The excess portion of thecylinder is then trimmed off. The thickness of the cast iron cylinder isnecessarily about 75 to 100 thousands of an inch. Substantial amounts ofmetal must be removed from the valve guide necessitating the use ofprecision drilling equipment. Numerous jigs, dies, guides and levelingdevices, and special power units are required with the system. As aresult a large capital investment is required to use the same. Further,the wear ability of the new valve guide is about the same as that of theoriginal valve guide.

Another system first drills an anchor hole in a valve guide. Then aself-piloting tap is threaded into the valve guide. A phosphor bronzespiral bushing is then threaded into the threaded valve guide with aspecial tool. Excess material is removed from the ends of the bushingand a broach is forced through the guide to set the bushing in place.The valve guide is then reamed to size. The tapping of the valve guideis a complicated operation and the insertion of the spiral bushing isdifficult.

I have now discovered still another system and method for rebuildingvalve guides wherein the use of a slotted tubular member as a valveguide permits a simple system of tools to be used to quickly, easily andeffectively rebuild the guides.

By various aspects of this invention one or more of the following, orother, objects can be obtained.

It is an object of this invention to provide a system and method forrebuilding valve guides wherein a few simple tools are employed.

It is another object of this invention to provide a system and methodfor quickly and easily rebuilding valve guides wherein the rebuilt valveguides have improved wear-characteristics.

lt is a further object of this invention to provide a system forrebuilding valve guides in which durable inserts used in the system areinexpensively and quickly made to the proper size needed for the job.

It is still another object of this invention to provide a system andmethod for rebuilding valve guides in which the valve guides are firstreamed but said reaming operation requires only simple and inexpensivetools.

It is yet another object of this invention to provide a method andsystem for rebuilding valve guides wherein the rebuilt guides havemaximum heat transfer properties to minimize wear of the rebuilt guides.

It is another object of this invention to provide an improved rebuiltvalve guide having improved wear characteristics and closer tolerancesfor more efficient engine operation.

Other aspects, objects, and the serveral advantages of this inventionare apparent to one skilled in the art from a study of this disclosure,the drawings, and the appended claims.

According to the invention there is provided a method for rebuildingvalve guides comprising the steps of reaming said valve guides so as toexpand the diameter thereof, forcing a tubular longitudinal insert intothe reamed valve guides to provide a new surface for the guide. Theinserts have an outer diameter greater than the inner diameter of thereamed hole and have a longitudinal slit extending the length thereof sothat the tubular member conforms in a press fit to the inner diameter ofthe reamed valve guide.

Further according to the invention, the metal of the insert isflowed tojoin the slit thereby preventing the oil from flowing through the slitwithin the valve guides. Preferably the tubular insert is made fromphosphor bronze for greater wearability of the rebuilt guides.

Further according to the invention, the tubular memher is formed byprogressively forming cut blanks from sheet stock into a tubular shape.The longitudinal slit in the tubular member can be formed by offsetportions such that the slit is nonlinear, or can be formed byinterengaging finger portions which abut each other at thecircumferential edges thereof.

Still further according to the invention there is provided a system forrebuilding valve guides comprising a means for reaming the valve guide,a tubular member having a slit extending longitudinally from one end tothe other and adapted to fit coextensively within said valve guide. Theouter diameter of the tubular member is slightly greater than the outerdiameter of the reaming means. Means are also provided for forcing thetubular member into a reamed valve guide, thereby making a press fitbetween the tubular member and the reamed valve guide.

Still further according to the invention a valve guide for an internalcombustion engine has a valve guide formed from a cylindrical hole inthe engine block, a cylindrical thin wall tubular member is firmlysecured in the cylindrical hole, the tubular member having alongitudinal seam from one end to the other. The wall thickness of thetubular member is preferably in the range of 10 to 25 thousands of aninch and the tubular member is preferably made from a phosphor bronze.

The invention will now be described with reference to the accompanyingdrawings in which:

FIG. I is a partial side elevational view in section of a typical valveguide and valve stem in operating position;

FIG. 2 is a view of the valve guide similar to FIG. 1 illustrating afirst step of the method of the invention;

FIG. 3 is a perspective view of a tubular insert used in practicing theinvention;

FIG. 4 is a side elevational view of the valve guide like FIG. 2, butshowing a second step of the process;

FIG. 5 is a side elevational view of the valve guide illustrated inFIGS. 2 and 4 showing a further step in the process;

FIG. 6 is a view similar to FIG. 5 showing the rebuilt valve guide aftera knurling operation;

FIG. 7 is a perspective view of a modified tubular member; and

FIG. 8 is a perspective view of still another modified tubular member.

Referring now to the drawings, and to FIG. I in particular, an overheadvalve engine head 10 has machined therein a valve guide 11 with anexposed shoulder portion indicated generally by the reference numeral 12through which the valve stem 13 is passed during assembly. Ordinarily,the exposed shoulder 12 will be integrally cast with the remainder ofthe head and thereafter machined to proper dimensions. A valve spring 14encircles exposed shoulder portion 12 of the valve guide assembly andthe valve is conventionally retained with respect thereto by a pair ofvalve keepers 18. While not shown, of course, the valve stem 13 extendsdownwardly and terminates in a valve portion having a suitable seatmachined into the lower surface of the head 10. The valve spring 14retains the valve in closed position with respect to the seat exceptwhen forced downwardly by a rocker arm (not shown) or the like in properoperational sequence. An oil seal prevents oil from flowing between thevalve stem 16 and the valve guide 11 and intothe combustion chamber ofthe engine.

The sea] 20 is retained in compressive abutment by means of theretaining boot assembly 22 which has a tubular base member 24adapted totelescopically engage the outer diameter of the valve guide 12 throughindent 26. The seal structure is more fully described and claimed inU.S. Pat. application Ser. No. 675,586, filed Oct. 16, I967.

Referring now to FIG. 2, there is shown a first step in the valverebuilding guide method. The valve stem 16 and its associated componentsare removed from the shoulder portion 12. A reamer tool having athreaded section 32 with a tapered leading portion 34 and a sizingportion 36 is forced through the valve guide. The reamer tool 30 is aself-piloting tool so that the axis of the reamed valve guide is thesame as the original axis of the guide. The reamer tool 30 has a reamersection comprised of longitudinal flutes 38 which cuts away and therebyexpands the diameter of the valve guide.

Referring now to FIG. 3 a tubular member 40 is stamped from a blank ofphosphor bronze and progressively formed into a tubular shape, leaving alongitudinal slit 42.

Referring now to FIG. 4, the tubular insert 40 is forced into the reamedvalve guide 11 by means of an adapter 44 having a tapered inner diameter46. The

outer diameter ofthe tubular member 40 is greater than the reamed valveguide 11' so that the tubular insert 40 must be radially compressed inorder to force the same into the reamed valve guide 11. The adaptor 44is annular shaped. At the upper portion, the inner diameter of theadaptor is greater than the outer diameter of the tubular insert 40. Atthe lower portion, the inner diameter of the adaptor 44 is equal to orless than the inner diameter of the reamed valve guide 11'.

A forcing tool 48 is positioned in the upper portion of the tubularinsert 40 and is struck at the top portion thereof to force the tubularinsert through the adaptor 44 and into the reamed valve guide 11. Theforcing tool 48 may have a lower circumferential rim as illustrated inthe drawing or may be flat.

The tubular insert 40 can be cut from a blank so as to be exactly thelength of the valve guide. Altemately standard size blanks can be usedwith an excess length trimmed off when the tubular members have beeninserted into the valve guides. Thus, when the tubular insert 40 iscompletely within the valve guide as illustrated in FIG. 5, with the topportion of the tubular insert 40 even with the top surface of theshoulder portion 12, the tubular insert 40 will be coextensive with thereamed valve guide 11 Further, the blanks are so dimensioned that theslit 42 is closed forming a longitudinal seam as the tubular insert isforced into the reamed valve guide. The wall thickness of the tubularinserts can be in the range of 10 to 25 thousands of an inch andpreferably in the range of IS to 20 thousands of an inch. Preferably thetubular inserts are made from phosphor bronze for maximum wearability.

At this point, the valve guide is ready for use. However, additionalsteps can also be performed to improve still further the rebuilt valveguide structure.

For example, as illustrated in FIG. 6, the inner surface of the tubularinsert 40 can be knurled as at 50 to flow the metal of the tubularinsert. This knurling process flows the metal of the tubular insert 40so as to seal off the passage through slit 42. By this step, the oilwithin the engine is prevented from seeping through the valve guide 11.In addition, the knurling operation more firmly seats the insert 40within the reamed valve guide. Many tools are available for thisknurling operation. One such tool is disclosed in U.S. Pat. No.3,038,253.

After the knurling operation, the valve guide can then be reamed againto a predetermined size diameter if necessary. The rebuilt valve guidewill then be as good as or better than the original valve guide of theengine.

In a modified procedure, the rebuilt valve guide illustrated in FIG. 5can be broached with a common breaching tool in order to flow the metalin the same manner as was done with the knurling tool.

The modified tubular insert 52 illustrated in FIG. 7 hascircumferentially offset slits 54 and 56 which are contiguous and form alongitudinal slit in the tubular insert. This modified tubular insert 52can be formed in the same manner as the tubular insert 40, i.e. stampedfrom tubular stock and progressively formed in dies into a tubularshape.

Another modified tubular insert 60 is illustrated in FIG. 8. Thismodified insert has interlocking fingers 62 and 64 which form in thetubular insert longitudinal slit 66 having a tortuous path. Theinterlocking fingers 62 and 64 abut at the circumferential edges thereofso that when the tubular member 60 is inserted within the valve guide,oil will not be able to flow through the longitudinal slit 66 from oneend to another. However, oil pockets can be left at the open slitportion 66 to provide oil retaining means for lubricating the valve stemwithin the valve guide.

This modified tubular insert 60 is formed in the same manner as thetubular insert 40, i.e. by stamping the same out of blanks of metal,preferably phosphor bronze, and then progressively forming the stampedblanks into a tubular shape as illustrated.

The use of the longitudinal slits facilitate the insertion of thetubular member into the reamed valve guide so that a press fit ismaintained between the tubular insert 40 and the reamed valve guide.Further, the formation of the tubular inserts are simple and inexpensivewith the stamping and forming operations. By the nature of theinterlocking relationship of the tubular inserts 52 and 60, no materialis wasted in the stamping operation.

The stamping operation is very precise and precision parts can be formedthereby. The tubular inserts formed by such process can be preciselyformed from thin gage phosphor bronze or other similar material. Thethinner the material is, the better the operation of the valve guides.The interface between the insert and the engine block retards the heatflow away from the valve guides during operation. It has been found thatas the wall thickness of the inserts decreases, the retarding effect ofthe interface decreases. Therefore, it is desirable to use as thin amaterial as possible without mitigating the wearability of the valveguide. By the use of the blanks, the wall thickness can be reduced toabout thousands of an inch.

Further, with the use of the sheet stock to form the tubular inserts,the final inner diameter of the valve guide can be controlled with fargreater accuracy than if the tubular inserts were cast or reamed.

A still further advantage of the use of the thin wall material is thatonly small amounts of material need be removed from the worn valveguides. This small amount of material can be removed with a single passof a self-piloting reaming tool disclosed above. In the prior artsystems, it is sometimes necessary to make multiple passes with reamingtools in order to remove enough material from the valve guide. Whensubstantial amounts of material are removed from the valve guide, aswith prior art systems, the alignment of the reaming tools is morecritical and must be controlled with more complicated equipment and morecomplicated procedures.

Reasonable variation and modification are possible with the scope of theforegiong disclosure, the drawings, and appended claims withoutdeparting from the spirit of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A method of rebuilding valve guides comprising the steps of:

reaming a valve guide so as to expand the diameter thereof:

providing a tubular metallic insert having an open longitudinal slitextending the length thereof, said slit being adapted to close uponradial compression of said insert, the outer diameter of said insert,with said slit completely closed under such radial compression,substantially equaling the diameter of said reamed guide;

forcing said insert into a tapered adapter having a minimum diametersubstantially equal to the diameter of said reamed guide and therebyradially compressing said insert and completely closing said slit;

positioning said adapter over said valve guide with said insert inalignment with said valve guide;

driving said insert through said adapter into said valve guide until theleading extremity of said insert is flush with the adapter-remoteextremity of said valve guide;

removing said adapter; and

trimming any excess portion of said insert such that said insert isthereafter substantially coextensive with said valve guide.

2. A method according to claim 1 further comprising the step of flowingthe metal of said insert after said insert has been driven into saidreamed valve guide to seal said slit thereby preventing oil from flowingthrough said slit within said valve guide.

3. A method according to claim 2 wherein said flowing step comprisesnarrowing the inner diameter of said insert.

4. The method according to claim 2 wherein said flowing step comprisesbroaching the inner surface of said insert.

5. The method of claim 2 further comprising the step of reaming saidinner surface of said insert after said flowing step to make apre-determined diameter bore for said valve guide.

6. A method according to claim 1 wherein said longitudinal slit isformed of interengaging finger portions which abut each other at thecircumferential edges thereof so as to prevent flow of oil through saidvalve guide.

7. A method according to claim 1 wherein said tubular insert is madefrom phosphor bronze.

8. A method according to claim 7 wherein the wall thickness of saidtubular insert is in the range of 10 to 25 thousands of an inch.

9. A method according to claim 1 wherein the wall thickness of saidtubular insert is in the range of 10 to 25 thousands of an inch.

10. A method according to claim 1 wherein said tubular insert is formedby progressively forming cut blanks from sheet stock into a tubularshape.

11. A method according to claim 1 wherein said longitudinal slit isformed by offset portions so that said slit is nonlinear.

12. A method according to claim 1 further comprising the step of reamingthe inner surface of said tubular insert after said tubular insert hasbeen forced into said reamed valve guide, so as to provide the innersurface of said tubular insert with a pre-determined inner diameter.

1. A method of rebuilding valve guides comprising the steps of: reaminga valve guide so as to expand the diameter thereof: providing a tubularmetallic insert having an open longitudinal slit extending the lengththereof, said slit being adapted to close upon radial compression ofsaid insert, the outer diameter of said insert, with said slitcompletely closed under such radial compression, substantially equalingthe diameter of said reamed guide; forcing said insert into a taperedadapter having a minimum diameter substantially equal to the diameter ofsaid reamed guide and thereby radially compressing said insert andcompletely closing said slit; positioning said adapter over said valveguide with said insert in alignment with said valve guide; driving saidinsert through said adapter into said valve guide until the leadingextremity of said insert is flush with the adapter-remote extremity ofsaid valve guide; removing said adapter; and trimming any excess portionof said insert such that said insert is thereafter substantiallycoextensive with said valve guide.
 2. A method according to claim 1further comprising the step of flowing the metal of said insert aftersaid insert has been driven into said reamed valve guide to seal saidslit thereby preventing oil from flowing through said slit within saidvalve guide.
 3. A method according to claim 2 wherein said flowing stepcomprises narrowing the inner diameter of said insert.
 4. The methodaccording to claim 2 wherein said flowing step comprises broaching theinner surface of said insert.
 5. The method of claim 2 furthercomprising the step of reaming said inner surface of said insert aftersaid flowing step to make a pre-determined diameter bore for said valveguide.
 6. A method according to claim 1 wherein said longitudinal slitis formed of interengaging finger portions which abut each other at thecircumferential edges thereof so as to prevent flow of oil through saidvalve guide.
 7. A method according to claim 1 wherein said tubularinsert is made from phosphor bronze.
 8. A method according to claim 7wherein the wall thickness of said tubular insert is in the range of 10to 25 thousands of an inch.
 9. A method according to claim 1 wherein thewall thickness of said tubular insert is in the range of 10 to 25thousands of an inch.
 10. A method according to claim 1 wherein saidtubular insert is formed by progressively forming cut blanks from sheetstock into a tubular shape.
 11. A method according to claim 1 whereinsaid longitudinal slit is formed by offset portions so that said slit isnonlinear.
 12. A method according to claim 1 further comprising the stepof reaming the inner surface of said tubular insert after said tubularinsert has been forced into said reamed valve guide, so as to providethe inner surface of said tubular insert with a pre-determined innerdiameter.